This invention relates to a method for treating edible oils. More particularly, the invention relates to a method for treating edible oils to remove excessive amounts of fatty acids present in the edible oils to render the edible oils more suitable for preparation of foods.
For a number of years in the United States, there has been an increasing use of edible oils such as crude and refined vegetable and marine oils and animal fats in the preparation of foods. Examples of such foods are the french fried potatoes, fried chicken and fried fish, etc., which are normally fried in shortening. The wide preference for such fried foods has brought about a substantial number of drive-in and regular restaurants which prepare and serve foods fried in shortening.
As is well known, shortening is generally prepared from fats and oils. Fats and oils are esters of higher fatty acids and a trihydric alcohol, glycerol. Such esters are known as glycerides. However, glycerides in shortening, as well as those in fats and oils, are subject to deterioration through contact with water or by thermal degradation. For example, the glycerides may be hydrolyzed to yield glycerol and free fatty acids or their salts.
In the frying of foods, some foods such as potatoes absorb a substantial amount of the edible oil, such as shortening, in which the food is being fried, so that there is a continuous depletion of the edible oil and the addition of fresh make-up oil. Other foods such as fish do not absorb appreciable amounts of oil and, therefore, the same batch of oil is used repeatedly for a long period of time. In the frying of such relatively non-absorbent foods, there is a tendency for free fatty acids to accumulate in the oil. Free fatty acids are extremely objectionable in foods and their presence in amounts exceeding about 1.2 or 1.3% by weight of the oil generally renders the oil unsuitable for use in frying foods.
From the above, it can be gathered that in the frying of a nonabsorbent food, such as fish, the edible oil is periodically observed for indications of degradation. When the fatty acids content of the oil exceeds the objectionable amount, it must be discarded. To my knowledge, there is nothing commercially available at the present time which can be used to extend the life of edible oil which contains an excessive amount of free fatty acids.
It is, accordingly, an object of the present invention to provide a method for extending the life of edible oil which contains excessive amounts of free fatty acids.
It is another object of the invention to provide an economical method for treating edible oil.
It is a further object of the present invention to provide a relatively simple method for removing free fatty acids from edible oils, which is economical and quick to use.
Further objects of the invention can be gathered from the following disclosure.